The Supermarine Spitfire Mk.Vb was the most widely produced variant of the Mk.V series of Spitfires. Entering service with the RAF in early 1941 the Mk.Vb variant incorporated a number of improvements over earlier Spitfires. Most notably it was the first common variant to be fitted with the B wing, comprising two 20mm cannons and four .303in Browning machine guns. This gave the Mk.Vb a big increase in firepower, something lacking from the earlier all machine gun armed Spitfires.

Also introduced were fishtail exhausts, giving a slightly improved exhaust thrust and therefore performance, metal covered ailerons, a deeper oil cooler and the front windscreen was also altered to one featuring an internally armoured section. The Malcolm Hood was also improved, offering a better overall view for the pilot.